and he was listing the most difficult things to find in the draft. QB of course is well known, but he specifically mentioned interior pass rusher as right up there in that top group because it is an extremely rare skill set; edge rusher for example is also difficult but you can find those guys much easier.
I recall that because to that point I'd never really considered it. Supply and demand due to rarity vs the value of taking away a QB's ability to step up. These guys come along every so often, but they're definitely very difficult to find.